Wireless communication system, base station, wireless terminal, and processing method implemented by base station

Abstract

A wireless communication system includes a base station and a plurality of wireless terminals that are capable of wirelessly communicating with the base station. The base station includes: a plurality of wireless apparatuses that form a plurality of cells; and a first processor configured to execute a first process including: determining a transmission power level for each of the cells in such a manner that a value obtained by totaling values of indexes for the plurality of cells becomes largest, the indexes each indicating a degree of fairness in communication opportunities among wireless terminals in a corresponding one of the plurality of cells. Each of the plurality of wireless terminals includes: a second processor configured to execute a second process including receiving, in a cell in which wireless terminals are present, a signal from each of the plurality of wireless apparatuses by using the transmission power level of the cell.

What is claimed is: 
     
         1 . A wireless communication system comprising a base station and a plurality of wireless terminals that are capable of wirelessly communicating with the base station, wherein
 the base station includes:
 a plurality of wireless apparatuses that form a plurality of cells; and 
 a first processor configured to execute a first process including: first determining a transmission power level for each of the cells in such a manner that a value obtained by totaling values of indexes for the plurality of cells becomes largest, the indexes each indicating a degree of fairness in communication opportunities among wireless terminals in a corresponding one of the plurality of cells, and 
   each of the plurality of wireless terminals includes:   a second processor configured to execute a second process including receiving, in a cell in which wireless terminals are present, a signal from each of the plurality of wireless apparatuses by using the transmission power level of the cell determined at the first determining.   
     
     
         2 . The wireless communication system according to  claim 1 , wherein the first process further includes second determining allocation among the plurality of wireless terminals for the transmission power level determined for each of the cells at the first determining, with respect to the plurality of wireless terminals that are present in each of the cells and are non-orthogonally multiplexed with one another during a non-orthogonal multiplex communication. 
     
     
         3 . The wireless communication system according to  claim 2 , wherein the first process further includes alternately executing a process of determining the transmission power level for each of the cells performed at the first determining and a process of determining the allocation among the plurality of wireless terminals performed at the second determining. 
     
     
         4 . The wireless communication system according to  claim 1 , wherein the receiving includes transmitting, after receiving the signal, channel quality information to the base station by each of the plurality of wireless terminals transmits, the channel quality information being approximated by an average interference amount from the cells other than the cell in which the each wireless terminal is present. 
     
     
         5 . The wireless communication system according to  claim 1 , wherein each of the plurality of wireless apparatuses included in the base station transmits and receives the signal to and from each of the plurality of wireless terminals by implementing a Multiple-Input and Multiple-Output (MIMO) method. 
     
     
         6 . The wireless communication system according to  claim 1 , wherein the first process includes determining the transmission power level for each of the cells based on a first resource allocation ratio corresponding to when the plurality of wireless terminals are subject to non-orthogonal multiplexing and a second resource allocation ratio corresponding to when the plurality of wireless terminals are not subject to the non-orthogonal multiplexing. 
     
     
         7 . A base station capable of wirelessly communicating with a plurality of wireless terminals, the base station comprising:
 a plurality of wireless apparatuses that form a plurality of cells; and   a processor configured to execute a process including: determining a transmission power level for each of the cells in such a manner that a value obtained by totaling values of indexes for the plurality of cells becomes largest, the indexes each indicating a degree of fairness in communication opportunities among wireless terminals in a corresponding one of the plurality of cells, wherein   each of the plurality of wireless apparatuses transmits, in a cell in which wireless terminals are present, a signal to the plurality of wireless terminals, by using the transmission power level determined for the cell at the determining.   
     
     
         8 . A wireless terminal capable of wirelessly communicating with a base station, the wireless terminal comprising:
 a processor configured to execute a process including: receiving a signal from a wireless apparatus forming a cell in which the wireless terminal is present, by using a cell transmission power level determined in such a manner that a value obtained by totaling values of indexes for a plurality of cells becomes largest, the indexes each indicating a degree of fairness in communication opportunities among wireless terminals in a corresponding one of the plurality of cells formed by a plurality of wireless apparatuses included in the base station.